Acute kidney injury in the perioperative setting

Perioperative acute kidney injury (AKI) is common and is associated with adverse clinical outcomes, excess mortality, and an increased risk for chronic renal failure. Recommendations to prevent perioperative AKI include the early identification of patients at risk, the avoidance of nephrotoxic drugs, and early goal-directed haemodynamic stabilization. The major causes for perioperative AKI are severe sepsis and septic shock, hypovolemia, bleeding and cardiac failure. The choice of modality, i.e. intermittent or continuous renal replacement (CRRT) therapy, can be made based on local resources. However, surgical patients frequently have impaired haemodynamics, a decreased pulmonary function and require removal of large amounts of fluid. In such cases, CRRT offers improved haemodynamic stability and volume control. Frequently, patients must be transferred to the operating theatre for redo procedures. Here, slow-extended daily dialysis treatments of 8-12 h can deliver a high dialysis dose with good haemodynamic stability at reduced costs. Surgical patients per se have an increased risk of bleeding. Regional citrate anticoagulation is a new and effective mode of anticoagulation which significantly reduces bleeding risk and transfusion requirements. Data from a recent meta-analysis show that, in surgical patients, mortality is reduced when renal replacement therapy is started early. In certain surgical diseases, i.e. acute occlusive disease of the abdominal aorta (Leriche's syndrome) following surgical reperfusion, patients are at risk of severe metabolic acidosis and life-threatening hyperkalemia. In such cases, intraoperative dialysis using a mobile batch system can help to avoid these complications by delivering an effective dialysis therapy at the time of reperfusion.